David Cameron has been accused of using international development as a "cynical weapon" to win over Tory backbenchers after a pledge to legally commit the government to spending on aid was dropped from the Queen's Speech.

Wednesday's speech, which set out the government's forthcoming legislative agenda, did not include a move to enshrine in law a promise to spend 0.7% of GNI (Gross National Income) on international aid.

The promise of a legal commitment was included in the Conservative Party 2010 manifesto as well as in the coalition agreement which stated: "We will honour our commitment to spend 0.7% of GNI on overseas aid from 2013, and to enshrine this commitment in law."

The Labour Party said the omission showed the "Tory party modernisation project is well and truly dead".

The 'Enough Food for Everyone IF' coalition of charities set up to fight global hunger said the failure to include such a measure in today's speech was a "missed opportunity".

IF spokesperson Sally Copley said : “International aid has already helped reduce the number of children dying from 12 million a year to 6.9 million and that work needs to continue.

"IF is now calling on the government to use its presidency of the G8 in Northern Ireland next month to ensure world leaders confront the causes of poverty and end the scandal of one in eight people going hungry."

And Ben Jackson, CEO of Bond- the membership organisation for NGOs working in international development- said the omission was "very disappointing".

"This was a missed opportunity for the Government to deliver its commitment to enshrine the UK’s aid promise. This legislation has cross-party support and was included in both the coalition agreement and the mid-term review," he said.

"Legislation would ensure that the UK continues to meet its aid promise for as long as it is needed and this would also send a strong signal to other leaders, many of whom will be in the UK for the G8 summit in June, that they too should meet and maintain their aid targets.”

The commitment to spend 0.7% of GNI on aid was a key part of David Cameron's Tory 'detoxification' strategy designed to show voters the party had moved towards the centre ground.

However a significant number of Conservative backbenchers are unhappy at money being spent overseas at a time of budget cuts at home.

Ivan Lewis, Labour's shadow international development secretary, said the omission showed the "Tory party modernisation project is well and truly dead".

Writing on The Huffington Post UK he said: "This lurch to the right underlines our concern that without legislation, we cannot be sure that this Government will keep its promise to deliver 0.7 target in future years and stop the aid budget being raided by other departments who are feeling the effects of swinging cuts."

"This is an important moment. If we don't stand up and be counted, do not be surprised if this turns out to be the thin edge of the wedge as UK aid is used as a cynical weapon in the battle for the soul of the Tory party, instead of a symbol of our national pride."